The transformation of light energy into electrical energy using photovoltaic (PV) systems has been known for a long time and these photovoltaic systems are increasingly being implemented in residential, commercial, and industrial applications. Although developments and improvements have been made to these photovoltaic systems over the last few years to improve their effectiveness and efficiency, continued improvement in effectiveness and efficiency of photovoltaic systems is being sought in order to make photovoltaic systems more economically viable.
Photovoltaic systems typically include, among other components, a photovoltaic array and a power converter. The photovoltaic array generates DC power and the power converter may be an inverter adapted to convert the DC power to AC power (e.g., single or three phase power). The power converter may perform an alternative function as well. For example, one power converter may convert an input DC voltage to a higher or lower output DC voltage. No matter the type of power converter used, it is often desirable to design and operate photovoltaic arrays so that the voltage that is input to the power converter is relatively high, and hence, current is low, in order to reduce costs associated with high-current elements, as well as to reduce energy losses associated with high currents.
Single photovoltaic arrays may operate in an open load state at 600 VDC. Two photovoltaic arrays operating as a bi-polar photovoltaic array system may operate in an open load state at 1200 VDC. Although photovoltaic array systems are capable of applying high open loaded voltages, array systems rarely run at or near this voltage because the loaded voltage of the array drops substantially once power is drawn from the arrays. For example, under a loaded condition, one typical bi-polar photovoltaic array system may operate at between 600 to 1000 VDC.